# Sparse- and low-rank approximation wiki

### From SparseSolver

Welcome to the sparse- and low-rank approximation wiki. This wiki has information on solvers and problems that arise in these fields (and subfields, such as compressed sensing).

Everyone is welcome and **encouraged to edit this wiki**; it runs on the same software as wikipedia. Please use common-sense and standard etiquette when editing. The first step to editing is to create an account. For an idea of where to start editing, see pages that are wanted. If you have an implementation of an algorithm, please link to it!

There are many excellent lists of related material on the web. This wiki is not trying to duplicate this information, but rather provide a less comprehensive but *more detailed* listing of available methods. The goal is that this website becomes a useful tool for practitioners searching for the ideal algorithm, and for researchers wanting to develop new methods.

**For new users**: when you create an account, please *do not include any numbers in your username* (or if you really want to, please email us first). There are many spam-bots that create accounts, so the administrators will automatically delete any account that appears to be suspicious, and this includes all usernames with numbers in them.

## Contents

The contents of this wiki have been organized into categories.

- Problems formulations that arise in sparse- and low-rank approximation.
- Solvers that are used for solving these problems. There are many sub-categories of solvers, such as:
- Convex solvers
- Greedy solvers
- Matrix completion solvers
- and many more (all of them listed at Solvers ).

- Benchmarking/Test problems for comparing algorithms
- Applications (in software) of sparsity or low-rank based techniques
- Hardware devices that perform compressed sensing.
- Other resources on the Internet.

If you have ideas for more categories, please go ahead and make them! But please check first to make sure that the new category is really necessary and won't duplicate a similar category.

## Want to contribute but not familiar with wiki software?

On this mediawiki software, all versions of a page are stored, so that it is always possible to undo edits at a later time. So have no fear! If you want to add content but do not know how to format it nicely, please go ahead and add the content, and then if necessary, someone else can format it later. We value content over style!

### The basics

Here are some examples. A link to an external website looks like: [http://www.google.com], which produces [1]

To be fancier, you can give the link a nicer name: [http://www.google.com google], which produces google

To make internal links in this wiki (which is encouraged!), use the format [[Other resources]], and this produces the link to the page Other resources.

If you want to name the link with a different name, use the format [[Other resources|Other internet resources]] to produce Other internet resources.

To make a bulleted list, start the line with a *

To add a page to a category (say, the "Convex Solvers" category), add [[Category:Convex Solvers]] to the page. If you want to *link* to the category "Convex Solvers", use [[:Category:Convex Solvers]] which gives Category:Convex Solvers. You can make the link have a nicer name by using the | operator again, e.g. [[:Category:Convex Solvers|Convex solvers category]] gives Convex solvers category.